The present invention relates to high speed pin printers and more particularly to pin control circuitry adapted for use in a high quality printer in which input data words, used to initiate pin actuations, are presented at a rate much faster than successive possible operations of any single pin, the purpose of the high data rate being to provide a lateral resolution of pin strikes which is even finer than the nominal diameter of the dot produced by each pin strike.
The function of the apparatus of the present invention is to respond to any fire bit present in each briefly presented input data word by generating a complex waveform of relatively long overall duration. The particular waveform generated has an energizing portion which effects the pin strike and a damping portion which aids the pin in coming to rest without undue oscillatory rebounding. The damping portion typically comprises a series of relatively brief pulses. To facilitate high speed operation in which successive pin strikes may be produced at minimum separation, the damping sequence is modified by shortening the series as a function of the timing of closely successive fire bits for a given pin.
Among the several objects of the present invention may be noted the provision of pin control circuitry for selectively energizing and then damping the rebound of the several pins employed in a multiple pin print head, in response to data words representing pin firing patterns; the provision of such apparatus in which data words may be presented at a rate faster than the possible repetitive firing of a given pin; the provision of such a system in which pins are fired with lateral resolution finer than the nominal diameter of the dot produced by the actuation of a single pin; the provision of such circuitry which is adaptable for widely varying pin fire repetition intervals; and the provision of such apparatus which is highly reliable and which is of relatively simple and inexpensive construction.